The study is part of a larger research project into hospitals’ performance in quality improvement campaigns for stroke patients, including the American Stroke Association-based “Get With the Guidelines.” It will appear in the November issue of the journal Stroke.
The drug in question, tissue plasminogen activator (tPA), is the only clot-dissolving drug approved in the treatment of strokes and can only be used within three hours after symptom onset, according to Eric E. Smith, lead author of the study and assistant neurologist at MGH Stroke Service.
Some doctors avoid using tPA at early stages of stroke onset because symptoms appear to be mild or improving, according to Smith. Some patients also arrive at the hospital too late for treatment and would have an increased risk of brain hemorrhaging if tPA were given, Smith said.
“This study found that 27 to 30 percent of these ‘too good to treat’ patients had worsening symptoms or died,” Smith said.
Researchers reviewed the records of 400 patients that came to the MGH emergency room between 2002 and 2004, and collected details from stroke registries, including the Paul Coverdell Stroke Registry at the Centers for Disease Control. Of the 128 stroke patients who arrived by the tPA treatment mark, 71 did not receive the drug. Of these patients, 41 were classified as “too good to treat,” while the others had undergone recent surgery or were on blood thinners.
The drug tPA is not without its risks, however, Smith noted, citing a landmark study in 1995 which suggested a 6 percent risk in brain hemorrhaging for tPA patients.
“Because tPA is a ‘clot-busting’ drug, the main complication is that it can cause bleeding for certain at-risk patients. Especially for these patients, doctors are more reluctant to use tPA immediately. They want to see if symptoms will get better on their own,” Smith said.
When symptoms improve early on for stroke victims, the blockage in the artery may still exist while the affected part of the brain borrows blood from other areas, Smith said.
As Smith explained, strokes are caused by lack of blood flow to part of the brain, usually when an artery is blocked by a blood clot. This part of the brain dies and can lead to paralysis, speech problems and numbness.
“Doctors should be more cautious when deciding not to use tPA early after stroke onset,” Smith said.
Smith said that it will take further research to find risk factors and a test for those who would have poor outcomes without tPA use.
While this study did not find any significant predictors, Smith said it “suggest[s] that more attention be paid to patients’ ability to walk—something that often is not evaluated—since gait disturbance was a reason why several could not go home,” according to an MGH press release.
“We really need a multi-centered approach so that further studies can be carried out with a larger pool of patients,” Smith said.
While advances in stroke treatments such as tPA and in clot-identifying technologies such as CT scans are positive strides, there is another important factor in fighting strokes, said Walter J. Koroshetz, director of MGH Stroke Service and co-author with Smith.
He said that educating patients about new technologies is as important as the developments themselves.
According to Koroshetz, “The main theme here is that things are changing rapidly, that the technology seems to be going ahead of patient education.”